/* Qilin - a Java Pointer Analysis Framework
 * Copyright (C) 2021-2030 Qilin developers
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation, either version 3.0 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Lesser Public License for more details.
 *
 * You should have received a copy of the GNU General Lesser Public
 * License along with this program.  If not, see
 * <https://www.gnu.org/licenses/lgpl-3.0.en.html>.
 */

package qilin.core.sets;

import java.util.Collection;
import java.util.Iterator;
import java.util.Set;
import qilin.core.pag.AllocNode;
import sootup.core.jimple.common.constant.ClassConstant;
import sootup.core.types.Type;

/**
 * A generic interface to some set of runtime objects computed by a pointer analysis.
 *
 * @author Ondrej Lhotak
 */
public interface PointsToSet {
  /** Returns true if this set contains no run-time objects. */
  boolean isEmpty();

  /** Returns true iff the set contains n. */
  boolean contains(AllocNode n);

  /** Returns true if this set shares some objects with other. */
  boolean hasNonEmptyIntersection(PointsToSet other);

  /** Set of all possible run-time types of objects in the set. */
  Set<Type> possibleTypes();

  /**
   * If this points-to set consists entirely of string constants, returns a set of these constant
   * strings. If this point-to set may contain something other than constant strings, returns null.
   */
  Set<String> possibleStringConstants();

  /**
   * If this points-to set consists entirely of objects of type java.lang.Class of a known class,
   * returns a set of ClassConstant's that are these classes. If this point-to set may contain
   * something else, returns null.
   */
  Set<ClassConstant> possibleClassConstants();

  /**
   * Size of objects in this set.
   *
   * @author Dongjie He
   */
  int size();

  /*
   * Empty this set.
   *
   * @author Dongjie He
   * */
  void clear();

  /**
   * Computes a hash code based on the contents of the points-to set. Note that hashCode() is not
   * overwritten on purpose. This is because Spark relies on comparison by object identity.
   */
  int pointsToSetHashCode();

  /**
   * Returns <code>true</code> if and only if other holds the same alloc nodes as this. Note that
   * equals() is not overwritten on purpose. This is because Spark relies on comparison by object
   * identity.
   */
  boolean pointsToSetEquals(Object other);

  PointsToSet toCIPointsToSet();

  Collection<AllocNode> toCollection();

  Iterator<AllocNode> iterator();
}
